(CNN) -- The highly anticipated update to the classic 1980s series "Sweet Valley High" is here. As we reported in July, "Sweet Valley Confidential" (St. Martin's Press) takes place 10 years after high school.

The series protagonists -- twin sisters Jessica and Elizabeth Wakefield -- are 27 now and on their own, no longer safely ensconced in the split-level, Spanish-style home of their parents. Their perfect figures, cascading blond hair and aquamarine eyes remain. And in case you need any reminders that the book takes place in modern times, there are references to Facebook, Google, Beyoncé and Justin Timberlake.

Jessica still lives in the idyllic Sweet Valley and has done something unforgivable to Elizabeth, who has since high-tailed it to New York, utterly brokenhearted. She is also bent on getting revenge, not a typical Elizabeth character trait.

CNN spoke to Sweet Valley creator Francine Pascal about the new book and the lasting legacy of the "Sweet Valley" franchise, which sold more than 150 million copies worldwide and was the first young adult series to hit The New York Times best-seller list.

"This is the first time in history that a kids' book has made the leap into adulthood," the author said. "And it's a very difficult thing because the people who used to read the books are people of importance, they're grown adults, and they have a certain ownership of 'Sweet Valley' because it was their adolescence. With the new book I hoped not to outrage them and I don't think I have. But I think I have surprised them in a lot of ways and I hope I have touched them."

Pascal, 73, said the inspiration for the first "Sweet Valley" book was the 1980s nighttime soap "Dallas." She figured that telling the story in series form would suit the soap opera format well because she wouldn't be tied in to providing closure -- she could feel free to leave readers hanging "with a hook ending and that would give it the feel of continuity."

Pascal said she selected the high school setting because she "needed a location that was complete in itself."

"High school is, after all, a microcosm of the real world," Pascal said. "It's the first time kids have some independence and have a world of their own where they're all together and they make the rules and live their life."

"High school is so serious," she continued. "There's friendship, pain, joy, betrayal, all those incredible things and the very essence of idealism." Pascal hinted that is exactly why the town of Sweet Valley and its inhabitants are so unbelievably perfect. It is just that -- an idealization.

Pascal said she intentionally made her main characters female because it was important "to do something where the girls drove the action. Up until then it was sort of a 'Sleeping Beauty' kind of thing where you had to wait for the boy to kiss you before you woke up, and this story I wanted to be in the hands of girls."

The author said she made the girls twins because she had always been fascinated by twins and she wanted "the opportunity to do a Jekyll and Hyde kind of thing where it's really the good and the bad of one person. So I conceived these impossibly (laughs) perfect people with very distinct personalities."

Surprisingly, Pascal concocted the picture-perfect Southern California town of Sweet Valley having never set foot in the state! "I thought about what was the best thing about your teenage years and it seemed to me it was summer," she said. "So I wanted a place where it was always summer and that's how I came to California."

"But I didn't actually come to California," Pascal said, "because at the time I had never been to California. Everything I knew about California came from MGM movies. A couple years later I went out there and it turned out it was just the way I thought it was."

When the first "Sweet Valley High" book, "Double Love," was published in 1983, Pascal said she had no idea it would be so successful.

"I remember two weeks after it came out the shock of seeing it on the Publisher's Weekly best-seller list," said Pascal. "I was stunned. This was in 1983 -- before the internet -- and I couldn't understand how everyone knew about it so fast. And it wasn't just the hundreds of thousands of readers who bought my four previous books. We were going into the millions."

Pascal is particularly proud that "Sweet Valley" turned a lot of young women on to reading.

"I used to get thousands of letters and about a quarter of them started the same way, 'I used to hate to read. ...'And that's the wonderful thing about this series; it really did bring a lot of young women into the reading world."

Ironically, librarians initially thumbed their noses at the notion of "Sweet Valley."

"At first they didn't even want to have the books in the library," Pascal said. "Until they saw girls who had never even set foot in the library before ask for them and then they relented."

Pascal, who divides her time between homes in New York and France, said if she were starting the series today, she wouldn't change much, "because I do feel the more things change the more they stay the same, particularly in adolescence. That's a unique time when many things are happening."

"These books were translated into 25 different languages," Pascal said. "Which makes you think: 'What does a girl in Indonesia have in common with these blond, blue-eyed girls in California?' Well, with the physical changes girls go through at that age comes a lot of feelings that are the same no matter where you are. So, the fact that there are cell phones and other technological advances now, those are all rather superficial. It's not how people are communicating, it is THE communication."

She pointed out that "Sweet Valley's" legacy lies in "the hundreds of thousands and perhaps even millions of girls who became readers because of 'Sweet Valley.' Otherwise they may have spent their lives captive of TV."

"Sweet Valley's" next incarnation will be a "Sweet Valley High" feature film written by Oscar-winning screenwriter Diablo Cody. Pascal said she believes Cody will do right by the series because, "She grew up with 'Sweet Valley' and she loved it." Pascal said she thinks the movie should take place in the 1980s, "Because I think all of the technological stuff is wrong for this. This is, well, a period piece."

Pascal said she is not quite sure what her involvement in the film will be. "I'd have to go back to the contract," she said. "It's something like story consultant. When material is adapted the original writers are not that involved. They don't hate them or, like in (Robert Altman's) 'The Player,' wish them dead or kill them. But it's gone from New York (laughs)."